Crater Lake

Crater Lake is a volcanic crater lake in south-central Oregon and the central feature of Crater Lake National Park, known for its deep blue color and exceptional water clarity. It fills part of a caldera 2,148 feet deep that formed about 7,700 years ago when the volcano Mount Mazama collapsed after erupting roughly 12 cubic miles of rhyodacite. With a depth of 1,949 feet it is the deepest lake in the United States and ranks tenth in the world for maximum depth and fifth for average depth. No rivers flow into or out of the lake; snow and rain balance evaporation so closely that its entire volume is replaced only about once every 150 years, and its surface holds two islands, Wizard Island and Phantom Ship.